Protective apparatus



March 28, 1939. E, LEACH 2,152,490

PROTECTIVE APPARATUS Filed Aug. 17, 1955 5 Sheets-Sheet 1 Inventor: IEdward A. Leach,

H is Attorn e g- March 28, 1939. LEACH PROTECTIVE APPARATUS 3Sheets-Sheet 2 Filed Aug. 17, 1935 Inventor". Edward A.L.eech,

b X/ f 9 His zttor-ney.

7 E. A. LEACH PROTECTIVE APPARATUS March 28, 1939.

Filed Aug. 17, 1935 5 Sheets-Sheet 3 II M F g.3 25% i-limu 5; Zn IumnEmil I jg 4 w I06 L. I08

Inventor: Ed ward A. Leach,

ttor ney.

Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE PROTECTIVE APPARATUSNew York Application August 17, 1935, Serial No. 36,752

19 Claims.

My invention'relates'to protective apparatus and-more particularly toapparatus for protecting the individual units of electrical apparatus ofa multi-unit system from faults while maintain- 5 ing in service thoseunits of the system which are free from fault.

While my invention is not limited thereto I contemplate its use moreparticularly in connection with high frequency apparatus such as carrierWave signal'transmitters and amplifiers. It has for one of its objectstoprovide a novel and improved form of protective system for suchapparatus.

In connection with high power broadcast transmitters, such as are usedfor radio program broadcasting, the continuity of service of thetransmitting equipment is of extreme importance. If, by reason of a.fault in an apparatus unit, such as an amplifier of said equipment, thetransmitter cannot be continued in service at its normal rated capacity,it is important to continue it in service at lower than normal capacity.In this way a large portion of the total area served by the transmittermay be afforded service which is substantially free from interruptionsdue to faults-in the transmitter equipment.

One of the objects of my invention, therefore, is to provide meanswhereby the individual units of the transmitting equipment may bedisabled and removed from service in response to a fault therein whilethe remainder of the equipment is continued in service. Thus, forexample, the transmitter provided with my invention. may comprise aplurality of amplifiers, any one of 5 which may fail at any time. Inaccordance with my invention means are provided automatically to removean amplifier in which a fault develops from service and to establishconnections whereby the other amplifiers are connected in operatingcircuit relation whereby the transmitter may be continued in servicewith somewhat reduced output.

-A further object of. my invention is to provide an improved switchingscheme for effecting the various control operations necessary to attainthe ends above set forth.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims. My inventionitself, however, both as to its organization and method of operation,together with further objects and advantages thereof, may best beunderstood. by reference to the following description taken inconnection with the accompanying drawings in which Fig. 1showsaschematically an embodiment of my'invention; Fig. 2 represents aside View of a portion of the switching structure involved; Figs. 3, 4,5, and 6 represent details thereof; and Figs. 7 and 8 represent endwiseviews. I

Referring to Fig. 1 of the drawings, I have illustrated my inventiontherein in its application to a high frequency transmitter. Thetransmitter represented in the figure comprises a plurality ofamplifiers indicated by rectangles I, 2, and 3, the output circuits ofwhich are normally connected in series by means of a common switchmeans, presently to be described, to supply amplified oscillations to anantenna 4; and the input circuits of. which are excited in parallel withoscillations to be amplified,- which oscillations, are supplied from anexciter 5. Both the input circuits and the output circuits of theseamplifiers, as well as the circuits for supplying operating potentialsthereto, are controlled by means of the unitary switch structure which Ishall now describe insofar as this structure is illustrated in Fig. 1.

This switchcomprises a shaft 8 which extends throughout the=transmitterin proximity to the amplifiers which are to be controlled. This shafthas mounted thereon, and positioned along the shaft, a number of sleevesI, 8, and 9 each of these sleeves corresponding to a respectiveamplifier. Each of these sleeves is arranged to be rotated about theshaft through a predetermined angle by means of its respective actuatingmechanism I, 8, 9. Each sleeve has fixedly attached thereto a group ofcross-arms I2, I3, I4; I5, IE, IT; I8, I9, 23; respectively. Thesecross-arms have mounted on their opposite ends conducting bridgeassemblies, which are conventionally indicated by members I2, I2; I3,I3"; I4, I4"; etc., each of which bridge members bridges a pair ofstationary contacts in a corresponding stationary contact bank. Thedifferent contact banks corresponding respectively to the differentcross-arms each include six contacts which will be referred to herein bythe reference letters a, b, c, d, e, and 1 respectively as applied onthe drawings to the contacts of the bank cooperating with cross-arm I2.

The switch is shown in its normal closed circuit position in which itwill be observed that the conducting bridge members I2, I3, I4, etc.each bridge the contacts b and c'of its respective bank, and the bridgemembers I2", I3", I4", etc. each bridge the contacts e and f of itsrespective bank. The shaft 6 may be operated to the right to move all ofthebridge 55 members away from the contacts with which they normallyengage. Any one or more of the actuating mechanisms 1', 8', 9 may thenbe actuated to rotate the respective sleeves thereby carrying the bridgemembers of the respective section of the switch about the shaft to aposition such that when the shaft is moved back to the left or to itscircuit closed position the respective bridge members l2, l3, l4 bridgecontacts a and b of their respective banks whereas the bridge membersl2, l3", l4 bridge the contacts at and e of their respective banks.

To produce this longitudinal movement of the shaft 6 it is normallybiased to the right by means of a spring 22 arranged at the right endthereof, and it is restrained against movement to the right by means ofa latch 23 and cam 24 shown at the left end of the shaft. The cam 24 ispivoted at the point 25 and the shaft is attached thereto at the point26 below the pivot. The lach 23 is provided with a roller 21 whichnormally lies behind a shoulder 28 on the cam thereby restraining theshaft in the position shown in the drawings. The upper end of the latch23 is attached to the armature of an electromagnet l whereby when themagnet is energized it is lifted to a position such that the roller 21releases the cam. The cam then rotates about its pivot 25 in acounterclockwise direction under influence of the spring 22 therebydisengaging all of the bridge members from the contacts of theirrespective banks. Any sleeve 1, 8, 9 may then be rotated on the shaft tothe alternate angular position with respect to the shaft whereupon theshaft may again be moved to the left.

To actuate the shaft to the left against spring 22 an actuatingmechanism which is connected to the cam at the point 2| is provided,this mechanism 6 being arranged when energized to rotate the cam in aclockwise direction to the position shown in the drawings where it isagain restrained by the roller 21.

The various actuating mechanisms 6', 1, 8, and 9 may be of any desiredtype but I prefer to employ an actuating mechanism of the type commonlyknown in the art as a Thrustor. One such mechanism, for example, isshown in United States Patent No. 1,935,432 to Lawrence S. Bourst,issued November 14, 1933. These devices commonly include a piston biasedto one position in a cylinder, and arranged to be operated to anotherposition in said cylinder by a suitable motor and pump arrangementwhereby a suitable fluid such as oil is pumped from one side of thepiston to the other. When the motor of the Thrustor is de-energized, thepiston returns under its bias to the initial position, forcing the oilback to the original side of the piston. The rate of movement of thepiston in both directions may be suitably regulated by control of therate of flow of oil. In this way the piston may be positively actuatedin either of its two directions in a sufficiently rapid but not abrupt,violent, or jerky, way.

In the drawings a rod 32 actuated by the piston of Thrustor 6' is shownas connected to the cam at the point 2|. The corresponding rods of eachof the rotating Thrustors 1', 8, 9' are attached to a lever 33 at anintermediate point thereof. This lever is pivoted at its righthand end,whereas at its lefthand end, it is connected by means of a contactcarrying member 34 to an arm 35, this arm being attached to therespective sleeves 1, 8, 9 whereby when the corresponding Thrustors 1,8', 9 is energized, the contact carrying member 34 is lifted causingrotation of the respective sleeve about the shaft 6. The contactcarrying members 34 each carry contacts 36 and 31 respectively, whichare arranged in circuits for effecting desired control operations whichwill later be explained.

Certain additional auxiliary switches are also provided and are actuatedby the movement of the cam 24. One of these comprises the switch 29.This switch is of the tumbler type having a control member or handle 30which is actuated upwardly and downwardly by prongs II project-- ingfrom a rack 3|. This rack 31 comprises a pair of parallel bars which areconnected together by members in the fashion of rungs of a ladder. It isarranged for motion longitudinally of itself upon supports 40 whichextend through longitudinal slots in the parallel bars and is actuatedby a tail member 38 attached to the cam member 24. This tail member 38extends through the rack in such a position that when the cam is rotatedin its counterclockwise direction it engages one of the rungs of therack and lifts the rack to an upper position. During this movement thelower prong II engages the control member 30 of the switch and operatesit to the upper position thereby closing the switch. This closing of theswitch 29 occurs fairly late in the counterclockwise motion of the cam.

During the clockwise motion of the cam 24 the rack 3| moves downwardlyuntil the upper prong ll engages the control member 30 of switch 29. Theweight of the rack is insufficient to operate the switch and the rackthus remains suspended until roller 27 drops behind shoulder 28. Member4| attached to latch 23 then engages one of the rungs of the rack withsufi'icient force to open switch 29.

The members II are illustrated as prongs for clearness of illustrationbut may comprise rungs of the ladder, member 30 projecting therebetweenand between the side rails of the ladder.

An additional auxiliary switch is indicated at 39. This switch islikewise one of the tumbler type having an actuating member 42 which isstraddled by the right bifurcated end of a lever 43. This lever ispivoted at an intermediate point and its left end is attached to the cam24 at a point at the left of the pivot 25 whereby the lever 43 isrotated about its own pivot in accordance with the motion of the cam.Thus when the cam is operated in a counterclockwise direction theactuating member 42 of the tumbler switch is moved upwardly to close thecontacts of the switch. This movement occurs fairly early in thecounterclockwise motion of the cam. When the cam is rotated in itsclockwise direction member 42 is moved downwardly thereby to open thecontacts of the tumbler switch. This opening of the contacts occurs latein the clockwise motion of the cam.

Two additional switches 44 and 45 are also shown, these switches beingconnected through a lever connection 46 with the armature of latchmagnet lfi whereby these switches are opened when the magnet isenergized and closed when the magnet is de-energized and roller 2! fallsbehind shoulder 28 of the cam.

The structure of the switch having been indi cated the circuits in whichit is connected will now be described. In the first place the variousamplifiers l, 2, and 3 of the transmitter may be of identicalconstruction, the circuits of amplifier I only being shown on thedrawings. It will be understood, however, that the showing of thisamplifier circuit is not complete, but is made only with such detail asto present a complete understanding of my present invention. While myinvention is, of course, not limited to any particular type ofamplifier, that represented in the drawings comprises a pair ofelectron. discharge devices 4'! connected in push pull relation, theiranodes being connected to opposite points on a tuned circuit 48, thelatter of which is coupled to an output coil 49. The output coils 49 ofall of the different amplifiers I, 2, and 3 are connected in series in acircuit which extends from ground at contactb of the left bank of theswitch through bridge member l2, output conductors 52 of amplifier l,bridge member i2", conductor 53, bridge member 65 output conductors 54of amplifier 2, bridge member 15', conductor 55, bridge member l8,output conductors 55 of amplifier 3, and bridge member l8 to the antenna4. Thus it will be seen that in the normal position of the switch theoutput circuits 52, 54, 55 of all of the amplifiers are connected inseries between the antenna A and ground.

The grids of each of the electron discharge devices 41 of the amplifierare connected to input conductors 5'5. These input circuits comprisingthe conductors 51 of amplifier l, conductors 58 of amplifier 2, andconductors 59 of amplifier 3 are all connected in parallel by the switchand are supplied with oscillations to be amplified from the exciter 5.The circuit for the input to amplifier I, for example, extends from oneside of the output of eXciter 5 through conductor 58, bridge member M ofthe switch, output conductors 5?, bridge member [4" of the switch, andconductor 52 to the other side of the output of the exciter. The circuitfor the input to amplifier 2 extends from conductor 59 through conductor53, bridge member H of the switch, conductors 58, bridge member I? ofthe switch, conductor 84 and conductor 82. A similar circuit may betraced through bridge members !9 and I9" for amplifier 3.

Anode potential for the discharge devices of amplifier l is suppliedthrough a conductor 65, bridge member I3 of the switch, conductor 66,modulation reactor 51, resistor 98, output of rectifier 69 to ground atE2. The rectifier 59 which is but conventionally indicated on thedrawings may be of any suitable type, but is shown as being suppliedwith three phase alternating current when switch 13 is closed.

Circuits similar to that last described may be traced for each of theother amplifiers through corresponding elements of the switch, thesecircuits entering the amplifiers through conductors l4 and 15respectively.

The grid bias potential for amplifier i is supplied through a circuitcomprising conductor 16, bridge member 13" of the switch and bias bus H.A similar connection for the other amplifiers through conductors I8 and19 respectively may readily be traced on the drawings.

The exciter 5 may comprise any suitable means for supplying highfrequency oscillations of appropriate voltage and power to theamplifiers i, 2, and 3. Polyphase power for energizing the exciter 5 isindicated as supplied through a switch 82 when this switch is closed.Thus the rectangle 5 may also represent suitable rectifying equipmentwhereby the circuits and instrumentalities for producing the highfrequency oscillationsare energized. The switches l3 and 82 forsupplying energizing potential for the rectifier 69 and exciter 5 areshown as of the electromagnetic type and adapted to be operated to theirclosed position when switches 44 and 45 are closed, and similarly theyare operated to their open position when these latter switches areopened. Manually operated switches 83 and 84 are shown as connected inseries with the windings of switches 82 and 13, which switches areclosed in the initial starting operation of the apparatus.

The anode circuits of each of the discharge devices 41 of the amplifierI include protective relays 85 and 85 which are normally insuflicientlyenergized to close their contacts, but which are operated to close theircontacts upon the occurrence of a current of abnormally large magnitudein the anode circuits of the respective discharge devices 41. When soenergized the contacts of these relays 85 and 86 remain closed even;afterthe winding of the relay again becomes de-energized or the currenttherein is reduced to a normal value. This is by reason of a latchdevice 81 provided on each of the relays whereby it is retained in itsclosed position. Similar relays are provided in each of the differentamplifiers in the manner illustrated and described in connection withthe amplifier l, although for simplicity of the drawings only a singlerelay 88 is shown in each of the rectangles 2 and 3 representing theother amplifiers.

To describe the operation of my invention let it be assumed that theswitches 83 and 94 have been actuated to their closed position and thattherefore the switches 82 and 13 are closed thereby to energize theexciter 5 and rectifier 69. Otherwise the apparatus is illustrated inthe drawings in its normal operating condition.

Let us now assume that a fault occurs in amplifier l which causesenergization of one or both of the relays 85, 85 causing these relays toclose both of their two pairs of contacts. A circuit is then completedwhich extends from positive voltage at bus 89 through the upper contactsof the operated relay 85, or 86, conductor 92, auxiliary switch 35 ofthe respective section of the switch, conductor 93, latch trip magnetIll, back to ground at bus 94. The latch magnet is thus energized andoperates its armature immediately to deenergize the actuating magnets ofswitches 82 and 13 whereby these switches are operated to their opencircuit position to remove operating potential from the exciter 5 andrectifier 69. Anode potential and exciting potential are thusimmediately removed from the amplifiers l, 2, and 3.

The armature of latch trip magnet IQ, of course, raises the latch member23 and roller 21 thereby releasing the cam 24 for counterclockwisemotion under influence of spring 22. After a slight counterclockwisemotion of the cam 24 sufficient to release the different bridge membersof the switch from the contacts with which they engage the tumblerswitch 39 closes its contacts. This completes a circuit which selectsthe rotating Thrustor corresponding to the amplifier I, this circuitextending from ground at bus 94 through switch 39, conductor 95,actuating mechanism of Thrustor I, conductor 96 and lower contacts ofthe operated relay 85, or 86. The Thrustor then actuates the lever 33upward which in turn rotates the sleeve I and all of the switch elementsmounted thereon about the shaft 6 and to a position such that the bridgemembers l2, l3, It each stand opposite the a and b contacts of theirrespective banks and the bridge "memiii bers I2, I3, and I4" each standopposite the Contacts d and e of its respective banks. Immediately afterthe initial upward movement of lever 33 produced by rotating Thruster I,switches 36 and 31 open. Switch 36 de-energizes the latch trip magnetII] which releases its armature and permits the roller 21 to fall uponthe surface 91 of the cam in which position it has no restraining eifectupon the movement of the cam. This holds the armature of latch magnet insuch a position that switches 44 and 45 remain open. Switch 31 producesan additional brealc in a circuit which extends from plus voltage at 98through the different switches 37, switch 29, and actuating mechanism ofthe Thrustor 6' to the negative side of the source at bus 94. Thisprevents energization of Thrustor 6' prior to completion of the rotarymotion of the section of the switch corresponding to the amplifier inwhich the fault occurred. This break in the circuit produced by switch31 is again closed by switch engaging its upper contacts when theThrustor I has substantially completed its upward motion. Also when thecam 24 has substantially completed its counterclockwise motion, switch30 closes thereby completing the last traced circuit for the actuatingmechanism of the main Thrustor 6. This Thrustor now applies forcethrough rod 32 rotating the cam 24 in the clockwise direction therebyoperating the shaft 6 to the left and moving all of the bridge membersinto engagement with the contacts standing opposite thereto.

As the cam approaches its final position switch 39 opens therebyde-energizing the rotating 'I'hrustor I. The rack 3I moves downwardlyuntil it is supported by control handle 30 of switch 29 its weight notbeing suihcient to actuate the toggle of this snap switch against itsspring bias. Shortly thereafter roller 2'! drops behind the shoulder 28.In dropping member 4I carried by latch 23 engages a rung of the ladderforcing it downward and opening switch 29. This de-energizes the mainThrustor 6'. The actuating magnets for switches 82 and I3 are nowenergized through switches and 44 respectively, whereby the exciter 5and rectifier 59 are again supplied with operating potential.

Amplifier I is now, however, completely removed from the circuit whereasamplifiers 2 and 3 are connected for operation. This will be seen froman inspection of the drawing wherein conductor 65 which formerlysupplied anode potential to discharge devices 41 is now connectedthrough bridge member I3 to ground at contact a of the correspondingbank of the switch. Similarly conductor I5, which formerly supplied biaspotential to the grids of the amplifier, is now connected through bridgemember I3" to ground at contact d of the respective bank. Outputconductors 52 of amplifier I are now open circuited at the contacts fand c of the switch bank with which they are connected; and the inputconductors 51 are now disconnected from the exciter 5 and instead, aregrounded at contacts a and d of the banlc with which they are connected.Thus, this amplifier completely removed from the circuit and theoperating potentials being removed therefrom, it may be entered by anoperator [or the purpose of effecting repairs.

Since the two sections of the switches corresponding respectively to theamplifiers 2 and 3 are now in the same position as formerly, theseamplifiers are in condition for normal operation, the only change intheir circuits residing in that the series connection of their outputcoils with the antenna 4 no longer includes the output coil 49 ofamplifier I, a short circuit comprising conductor 99 having beensubstituted instead, this conductor extending between contacts a and dof the lefthand bank of the switch.

For the purpose of clarity this antenna circuit will again be described.It now extends from the ground at contact 2) of the left bank of theswitch through bridge member I2, to contact a, conductor 99, contact d,bridge member I2", contact 6, conductor 53, bridge member l5, outputcircuit 54 of amplifier 2, bridge member I5, conductor 55, bridge memberI8, output circuit 56 of amplifier 3, and bridge member I8" to antenna4,

Thus the equipment is again in readiness for operation. Had the faultoccurred in either of the other amplifiers, a similar cycle ofoperations would have been completed to remove the respective amplifierand to re-establish connections for the remainder of the amplifiers.Similarly, two or all of the amplifiers may be removed in the event thatfaults occur therein.

Let us assume now that it be desired to restore the amplifier I toservice after it has been removed in response to a fault. Each of thelatch devices 8'! is shown as provided with a handle whereby thearmature of the respective relay may be released to open its contacts.This having been effected, the operator may then operate switch I02 toits closed position, thereby directly energizing the latch trip coil ID.This trip coil immediately opens the switches 44 and 45 to removeoperating potential from the exciter 5 and rectifier 69 thereby tode-energize all of the amplifiers. Cam 24 is released by roller 21 andcompletes its cycle of operations. Since, however, relays 85 and 86 arenow de-energized, the rotating Thrustor I is de'energized whereupon therod 32 actuated by the Thrustor I again lowers under bias of theThrustor and additional spring pressure, if desired, causing the sleeve"I to be rotated to the position shown in the drawings. When thisrotation is substantially completed switch 31 closes its break in thecircuit for the main Thrustor. Switch 29 is also actuated as previouslydescribed to complete this circuit. The main Thrustor then rotates thecam 24 in the clockwise direction until the roller 21 again drops behindthe shoulder 28 when it becomes de-energized. The switch is thenrestored to the position shown in the drawings and all of the amplifiersare in their normal operating condition.

Any desired means for modulating the oscillations amplified byamplifiers I, 2 and 3 may be employed. This means is illustrated on thedrawings by the rectangle I30 which may represent a conventional Heisingmodulator whereby the voltage on modulation reactor 67 is varied inaccordance with signal currents produced by microphone I3I.

Of course, if, in a particular application of the switching schemeprovided in accordance with my invention, as, for example, in connectionwith the grid circuits of vacuum tubes it be desired to shorten the gridleads leading to the switch, then switches of a suitable type, forexample, knife blade switches may be employed. Such switches may beplaced directly in the apparatus unit and controlled from acorresponding sleeve I, 8, 9 of the isolation switch through a suitablelever mechanism.

In Fig. 2 of the drawings I have shown a side view of that section ofthe switch which corresponds to amplifier 3, the remaining sectionsbeing, of course, substantially identical. The rod 6 is shown mounted ina suitable framework I03 and is biased to the right by means of thespring 22 previously referred to. Sleeve 9 is also more clearly shown inthis figure, the cross-arms I8,

" I9, and 20 being attached thereto by disks I04 I'll arranged onopposite sides thereof and bolted together in a manner yet more clearlyto be described in connection with the other figures. Conducting bridgeassemblies I8, I"; I9, I9"; 20, 20", are shown mounted upon the ends ofthese cross-arms in engagement with their respective contacts b and c,and e and d.

The manner of assembly of the shaft 6, sleeve 9, cross-arms, and bridgeassemblies may better be understood from Figs. 3 to 6 inclusive. Fig. 3shows that section of the shaft 6 extending through the portion of theswitch shown in Fig. 2, the end of the shaft being attached by asuitable screwthread and nut arrangement I05 to a rod I00 which isattached to and biased by the spring 22. On the rod 6 is mounted thesleeve 9 which is broken away to indicate length, this sleeve havingsecurely attached thereto the arm 35 by which it may be rotated. Thisarm is securely attached to a collar I08 which is riveted to the sleeve9 and which has an outer ball race I09 seated therein. This ball racealigns with inner ball race M0, the latter being mounted on the rod 5.An additional collar I I I serves as a spacing member for retaining theball races within the collar I08. The opposite end of the sleeve 9 isundercut at II2 to fit over a collar H3 which is arranged between theend of the sleeve 9 and an additional collar II4 which is securelyattached to the shaft 6. Thus the sleeve 9 is held securely in itslongitudinal position upon the shaft 6 but is arranged for free rotationthereon.

Figs. 4 and 5 show the method of attachment of the cross-arms to thesleeve 9. Each sleeve has mounted upon it a flat-sided member H5 whichis held securely in place upon the sleeve by means of the set screw IIEshown in Fig. 5. The cross-arms each comprise a pair of nonconductingbars III which extend in parallel relation and are bolted to theopposite sides of the member H5 by means of bolts H9 extending throughdisks I04 on opposite sides of the two bars, these bolts engaging theopposite square sides of the collar H5.

Fig. 4 is a sectional view on the line 4-4 of Fig. 5 from whichconsideration a somewhat better idea of the arrangement may be obtained.

Fig. 6 is a view partially in section showing the bridge assembliesmounted upon bars II! of the cross-arms. Each of these assembliescomprises a conducting shield IZI which partially houses the flexiblecontact brushes I22 which engage the stationary contacts I23. Thesecontact brushes I22 are secured within the shield I2I by riveting to anintermediate member I24, which intermediate member is securely fastenedto the shield. A screw I25 projects through a clamping member I25 on theopposite side of the members I27 whereby the shield MI and contacts I22are securely attached to the cross-arm.

It will be observed that when the switch is in its circuit closingposition the brushes I22 engage their contacts with a certain amount ofspring pressure. The switches 29 and 39 of Fig. I are operated inproperly spaced sequence in the cycle of operation to the switch so thatthis spring pressure is released before any rotation of the respectivecross-arm occurs, and is reapplied only after rotation of the cross-armis completed. The contacts I23 are shown as provided at the lower endsthereof with corona shields I26 and as supported by non-conductingsupports I21 from the framework of the switch. The holes I28 areprovided in each of the contacts for the purpose of making electricalconnections therewith in any suitable manner.

Fig. '7 is an end view of the switch showing the arrangement of thecontacts, cross-arms comprising bars I", disks I04, member H5, andsleeve 9, together with the contact assemblies I2I.

Fig. 8 is an end view of the equipment on line 8 of Fig. 2 and shows therotating Thrustor 9' which is adapted when energized to operate thelever 33 upward thereby to lift the arm 35 against the bias of springI29 to rotate the sleeve 9. Lever 33 also actuates contact carryingmember 34 which operates switches housed within a container I32 andwhich are indicated in Fig. 1 as switches 36 and 31.

While, by way of illustrating the principles of my invention I haveshown means responsive only to particular types of faults to isolate theapparatus unit in which the fault occurs it is obvious that it may beutilized by a person skilled in the art to effect such isolation inresponse to practically any condition in the apparatus units whichrenders it desirable to effect such isolation, and that by the termfault as used in this specification I have reference to any suchcondition.

While I have described my invention in connection with a radiotransmitter, it will be understood that it is not limited thereto, andthat I contemplate its use generally in the protection of multiple unitelectrical apparatus.

While I have shown a particular embodiment of my invention, it will ofcourse be understood that I do not wish to be limited thereto, sincemany modifications may be made both in the circuits shown and theinstrumentalities employed. I contemplate by the appended claims tocover any such modifications as fall within the true spirit and scope ofmy invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. The combination, in a switching scheme, of a plurality of electricaloperating units, switching means individual to each of said units forconnecting said units to a circuit common to all of said units, commonactuating means for said individual switching means, and individualactuating means therefor, said common actuating means being responsiveto a fault in any of said units to operate all of said individualswitching means to disconnect individually each of the different unitsfrom said circuit, and means responsive to the fault to operate theactuating means individual to the unit in which the fault occurred toalter the respective individual switching means, and subsequently toactuate said common actuating means to connect the other of said unitsto said circuit while said one unit in which said fault occurred remainsdisconnected.

2. The combination, of a plurality of operating units connected inoperating circuit relation to each other, a unitary switch structurehaving actuating mechanism therefor, said actuating mechanism comprisingan actuating mechanism common to all of said units and a plurality ofindividual actuating mechanisms, each corresponding to a respective oneof said units, means responsive to a fault in any of said units tooperate said common actuating mechanism and the individual actuatingmechanism corresponding to the respective unit, means included in saidunitary switch structure responsive to operation of said actuatingmechanisms to interrupt operation of all of said units, to disconnectsaid unit in which the fault occurred from operating circuit relationwith the other of said units, and to reconnect the other of said unitsfor operation.

3. The combination, in a switching scheme, of a plurality of electricaloperating units, switching means individual to each of saidunits forconnecting said units to a circuit common to all of said units, each ofsaid switching means having an open circuit position and a closedcircuit position, means responsive to a fault in any of said units tooperate all of said switching means to open circuit position, meansoperative while said switching means are in the open circuit position toalter the condition of the switching means corresponding to the unit inwhich the fault occurred to disconnect said unit from said circuit whensaid switching means are operated to the circuit closed position, andmeans to operate all of said switching means to the circuit closedposition.

4. The combination, in a switching scheme, of a plurality of electricaloperating units, switching means individual to each of said units forconnecting said units to a circuit common to all of said units, meansresponsive to a fault in any of said units to operate all of saidswitching means to disconnect individually each of the different unitsfrom said circuit and again to operate all of said switches to closedcircuit position, and means responsive to said fault in one of saidunits to alter the condition of the respective switching means in such away that when said respective switching means is operated to its closedposition said one unit is disabled by said switching means.

5. The combination, in a switching scheme, of a plurality of electricalunits connected in operating circuit relation with each other, each unitincluding a switch, means in each unit to actuate the respective switchin response to a fault in the corresponding unit, means responsive to afault in any of said units to actuate all of said switches, and means tocoordinate the actions of said different actuating means in such a waythat in response to a fault in any unit said unit is disconnected fromsaid operating circuit relation with the other units and an operatingcircuit for the other units is completed through the unit in which thefault occurred.

6. The combination, in a switching scheme, of a plurality of electricalunits electrically connected together, each unit including switchingmeans, said switching means comprising a movable switch member andstationary contacts cooperating therewith, means responsive to a faultin any of said operating units to actuate all of said members to opencircuit position, to alter the switching means in the unit in which saidfault occurred in such a way that when said member is again actuated toclosed circuit position it disengages certain of the contacts with whichit previously engaged, and subsequently to actuate all of said membersto closed circuit position, and means including circuit connectionsthrough said contacts whereby after operation of said fault responsivemeans the unit in which said fault occurred is disconnected by saidmember from the other of said units and the other of said units remainconnected together.

'7. The combination, of a switch actuating member adapted forlongitudinal movement, a plurality of movable contact members carriedthereby arranged for substantially simultaneous longitudinal movementtherewith from circuit closed position to circuit opened position andalso to rotate thereon, means to operate said actuating member to moveall of said contacts longitudinally thereof from one of said positionsto the other, and means selectively to rotate any of said contactmembers while all of said contact members are in the open circuitposition.

8. The combination, of a switch actuating member adapted forlongitudinal movement, a plurality of movable contact members carriedthereby arranged for longitudinal movement therewith and also to rotatethereon, stationary contacts cooperating with each of said movablecontact members, apparatus units corresponding to each of said movablecontact members, said units being connected in operating circuitrelation thereby, means responsive to a fault in any of said apparatusunits to operate said actuating member to move all of said contactmembers longitudinally thereof selectively to rotate the contact membercorresponding to the unit in which the fault occurred, and subsequentlyto return said actuating member to its original position, and meansincluding circuit connections whereby said unit in which said faultoccurred is removed from said circuit relation by the respective movablecontact member after operation of said fault responsive means.

9. The combination, of a switch actuating member adapted forlongitudinal movement, a plurality of movable contact members carriedthereby arranged for longitudinal movement therewith and also to rotatethereon, stationary contacts cooperating with each of said movablecontact members, a plurality of apparatus units, each of said unitsincluding an electron discharge device, and each unit corresponding to adifferent one of said movable contact members, means comprising saidcontact members to connect said discharge device in operating circuitrelation and to supply operating voltage thereto, and means responsiveto a fault in any of said apparatus units to operate said member to moveall of said contact members longitudinally thereof, selectively torotate the contact member in which the fault occurred and subsequentlyto return said member to its original position and, connections wherebysaid operating voltage is removed from the discharge device of the unitin which said fault occurred by said rotated member and said unit isdisconnected from circuit relation with the other units.

10. In combination, a plurality of electron discharge apparatus unitsconnected in operating circuit relation, means to supply operatingvoltage to each of said units, means responsive to a fault in any ofsaid units to remove operating voltage from all of said units, todisconnect said unit in which said fault occurred from operating circuitrelation with the other of said units and subsequently to connect saidother of said units for operation and means to reoperate said last meansto reconnect said unit in which said fault occurred in operating circuitrelation with the other units.

11. In combination, a plurality of amplifiers, each of said amplifiershaving an output, means connecting said outputs in series, meansresponsive to a fault in any of said amplifiers to deenergize all ofsaid amplifiers, to disconnect said amplifier in which the faultoccurred from said series connection, to establish an output connectionfor the other of said amplifiers and to re-energize said other of saidamplifiers.

12. In combination, a plurality of amplifiers, means connecting saidamplifiers in operating circuit relation to each other, means responsiveto a fault in any of said amplifiers to de-energize all of saidamplifiers, to disconnect the amplifier in which said fault occurredfrom operative relation with said other amplifiers, and to reconnect theother of said amplifiers in operating circuit relation with each other,and means to operate said last means to restore said amplifier in whichsaid fault occurred to operating circuit relation with the otheramplifiers when said fault has cleared.

13. In combination, a plurality of electrical apparatus units, a switchstructure, said switch structure comprising a shaft arranged forlongitudinal movement, a plurality of contact members correspondingrespectively to each of said apparatus units individually mounted forrotation on said shaft and for movement longitudinally of said shaft,stationary contacts cooperating with said contact members, connectionsthrough said contact members and respective stationary contacts wherebysaid units are connected in electrical circuit relation, meansresponsive to a fault in any of said apparatus units to operate saidshaft longitudinally to release said contact members from said contacts,torotate the contact members corresponding to the unit in which saidfault occurred and then to return said shaft to its original position,and connections whereby said one unit is isolated from circuit relationwith said other. of said units when said shaft is returned.

14. In combination, a plurality of electrical apparatus units, a switchstructure, said switch structure comprising a shaft arranged forlongitudinal movement, a plurality of contact members correspondingrespectively to each of said apparatus units individually mounted forrotation on said shaft and for movement longitudinally of said shaft,stationary contacts cooperating with said contact members, connectionsthrough said contact members and respective stationary contacts wherebysaid units are connected in electrical circuit relation, meansresponsive to a fault in any of said apparatus units to operate saidshaft longitudinally to release said contact members from saidstationary contacts, means responsive to said movement of the shaft torotate the contact members corresponding to the unit in which said faultoccurred and then to return said shaft to its Original position, andconnections whereby said one unit is isolated from said other of saidunits when said shaft is returned.

15. The combination, in a high frequency apparatus, comprising aplurality of units connected in operating circuit relation of a relayassociated with each unit, means associated with each unit responsive toa fault of predetermined character in said unit to operate said relay,and means responsive to operation of any of said relays to deenergizeall of said units, to disconnect said one unit from the other unitswhile said units are deenergized, and again to energize the other ofsaid units while said one unit remains deenergized.

16. In combination, a plurality of electron discharge apparatus unitsoperating at high frequency, said units being connected in a common highfrequency circuit extending through all of said units, and meansresponsive to a fault in any of said units to deenergize all of saidunits, subsequently to disconnect the unit in which the fault occurredfrom said common high frequency circuit and to complete said highfrequency circuit through the other units both while said units aredeenergized, and then to reenergize said other units.

1'7. In combination, a plurality of electron discharge apparatus unitsoperating at high frequency, said units being connected in a common highfrequency circuit extending through all of said units, energizing meansfor each of said units, means responsive to a fault in any of said unitsto deenergize all of said units, to disconnect the unit in which thefault occurred from said common high frequency circuit and subsequentlyto reenergize the other units, and means to reoperate said last means todeenergize all of said units, to reconnect the unit in which the faultoccurred in circuit relation with the other units While all of saidunits are deenergized, and then to reenergize all of said units.

18. In combination, a plurality of high frequency amplifiers connectedin circuit relation with respect to currents amplified thereby, meansresponsive to a fault in any of said amplifiers to deenergize all ofsaid amplifiers, to disconnect the amplifier in which the fault occurredfrom the other amplifier, to reconnect the other amplifiers in circuitrelation with each other, and to reenergize said other amplifier, andmeans to reoperate said last means to reconnect the amplifier in whichthe fault occurred in operating circuit relation with the otheramplifier.

19. In combination, a plurality of high frequency amplifiers connectedin circuit relation with respect to currents amplified thereby, means toenergize the different amplifiers for operation, means responsive to afault in any of said amplifiers to deenergize all of said amplifiers, todisconnect the amplifier in which the fault occurred from the otheramplifiers and subsequently to reenergize the other amplifiers foroperation, and means to reoperate said last means to reconnect theamplifier in which the fault occurred in operating circuit relation withthe other amplifiers.

EDWARD A. LEACH.

